atomic structure

atomic structure

1. John Daltons Atomic theory (1808)

   • all matter is made up of atoms
   • Atoms cannot be created of destroyed and are indivisable.
     • the idea was replaced with the discovery of subatomic particles

2. discovery of cathode rays by William Crookes

   • examined what happened when an electric current was passed through a glass vacuum tube.
   • showed the existence of cathode rays
     • *streams of charged particles coming from the negative electrode or cathode
   • when an object (eg. Maltese Cross) was placed the the pathe of the ras a shadow was cast

3. milikans oildrop experiment

   • measure the charge on an electron
     • this meant the mass of an electron could also be measured >charge to mass ratio

4. jj thompson

   • Discovery of the electron
     • proved that cathode rays are negative
     • called electrons (George Stoney
     • also discovered charge to mass ratio = e/m
   • plum pudding model of the atom
     • atom was a sphere
     • possitive and negative bits in
     • electrically neautral

5. rutherford

   • discovery of the nucleus
     • bolbarded gold foil with alpha particles
     • majority passed through ... alot of empty space on an atom
     • some were repelled ... positive charge
     • rebounded hit the nucleus
   • discovered the proton

6. chadwicks discovery of the neuton

   • during an experiment he fond that neutral particles were being emitted from the nucleus
   • same mass no. as a proton